Cartridge case exterior as inner surface of arcuate gun nozzles



1951 c w. MUSSER 2,96

CARTRIDGE CASE EXTERIOR AS INNER SURFACE OF ARCUATE GUN NOZZLES FiledJuly 29, 1958 INVEN TOR. C WALTON MUSSER CARTRIDGE CASE EXTERIOR ASINNER SUR- FACE OF ARCUATE GUN N OZZLES C Walton Musser, Beverly, Mass.,assignor to the United States of America as represented by the Secretaryof the Army Filed July 29, 1958, Ser. No. 751,807

1 Claim. (Cl. 89-1.7)

(Granted under Title 35, US. Code (1952), see. 266) The inventiondescribed herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment of any royalty thereon.

This invention relates to a recoilless gun in combination with acartridge case for fixed ammunition and has for an object to provide alighter weight recoilless type gun by having such a case for recoillessrifles in which the rear exterior surface of the case forms wallportions of arcuate venturi gun nozzles.

A further object is to provide a rifle of shorter length due to theabsence of the breechblock and breech mechamsm.

A still further object is to facilitate manufacture of rifles byreducing the complexity of machining problems inherent in producingconventional nozzles heretofore either machined from solid bar stock orassembled from several carefully fitted pieces machined from forgings orbar stock whereby the inner surface of the annular nozzle was, ofnecessity in either case, larger than the case diameter. This is causedby the requirement of breech loading and consequently the cartridge caseis inserted through a hole in the breech whose outer surface forms theinner portion of the annular nozzle. This increases the overall diameterof the weapon with an attendant increase in weight. For example, a 105mm. rifle with the hitherto conventional annular nozzle is about ten andone-half /2) inches in diameter at the breech, while a rifle utilizingthe cartridge case as the inner surface of the annular nozzle is onlysix and three-quarters (6%) inches in diameter, resulting in anappreciable reduction in weight of the gun.

A preferred embodiment of the invention is illustrated in theaccompanying drawing, wherein:

Fig. 1 is a vertical cross section of Fig. 2 taken along line 1-1showing the cartridge case exterior as the inner surface of an annularventuri.

Fig. 2 is an end view of the recoilless rifle with the cartridge case inplace.

Similar numerals refer to similar parts throughout the several views.

As illustrated in Fig. 1, chamber 1 of the rifle has a barrel 2 screwedto its forward end, the opposite end having a locally reduced diameter 3which, in conjunction with the outside rear diameter 4 of the cartridgecase, constitutes the annular venturi 5. From this point rearward thechamber wall 8 expands in diameter to 9 while the case continuesrearward at essentially a uniform outside diameter forming the exit 10of the venturi section.

Actuation of the primer 7 causes the powder 16 in the cartridge case 6to ignite, the gases resulting therefrom moving radially outward throughthe case openings 17 into the chamber area 1A in which they change theirdirection and flow rearwardly through the annular venturi openings 5between the inwardly extending projections 13, radial spiders makingtheir final exit at 10.

The cartridge case is inserted into the chamber of the rifle untilshoulder 11 on the case abuts the chamber end 12 of the barrel. Theshoulder 11 being interrupted so that it can pass the spider 13. In thisposition the lugs 15 or interrupted threads on the case are adjacent thegrooves 14 cut in the spiders 13 that extend radially inward beingintegral with the expanding walls of the chamber. Rotation of the casein either clockwise or counterclockwise direction a predeterminedangular distance results in the cartridge case threads becoming engagedwith the grooves in the spider, thereby preventing rearward ejection ofthe projectile during firing.

Fig. 2 is a full end view of Fig. 1 showing the segmented annularventuri 5 between the radially inward projecting spiders 13 and theengaged lugs or threads 15 on the cartridge case whereby the cartridgecase is securely held in place during firing.

It will be apparent from the foregoing detailed description that manyvariations, modifications and deviations from the specific embodimentdisclosed will occur to one skilled in the art without departing fromthe spirit and scope of the present invention and I therefore intend tobe limited only in accordance with the following claim. The outer wallsof chambers 1 and 8, and the generally radial walls of the spider 13constitute an enlargement secured to the barrel 2 as illustrated.

I claim:

In a recoilless type gun having a barrel, a projectile receiving chamberin a rear portion of said barrel, a cartridge case secured to aprojectile, the side walls of said cartridge case being perforate forradial emission of the products of combustion of propellant, and anenlargement forming venturi passageways at least in part and secured tosaid barrel around said projectile receiving chamber, the combinationtherewith of the improvement enabling the length and weight of said gunto be substantially reduced by having a rear cylindrical wall surface ofsaid cartridge case serve as venturi inner wall portions, saidimprovement including a spider forming a support for a rear portion ofsaid cartridge case behind its perforate portion, said spider beingintegral with said enlargement and forming a plurality of generallyradial walls separating said venturi passageways, the cartridgesupporting radially inner end surfaces of at least some of said wallsbeing provided at least one lug receiving groove, and lugs on saidcartridge case for reception in said grooves on rotation of saidcartridge case with re spect to said gun and its enlargement, said wallsbeing angularly spaced to leave portions of the cartridge casecylindrical surface exposed to products of combustion and whereby suchsurface portions of the cartridge case may serve as radially inner wallsof said venturi passageways and the total weight of the recoilless gungreatly reduced.

References Cited in the file of this patent UNITED STATES PATENTS2,421,522 Pope June 3, 1947 2,572,111 Kroeger et al. June 7, 19492,598,256 Hickman May 27, 1952 2,791,961 Musser May 14, 1957 2,834,255Musser May 13, 1958 FOREIGN PATENTS 139,773 Germany Apr. 3, 1903

